Generally, containers, which contain food and beverages such as mineral water and liquid materials such as oil, paint, chemicals, and the like, have a neck to allow a liquid material to enter and exit therethrough.
In addition, a container is provided, at a neck thereof, with a cap for opening or closing an opening of the neck to limit the inflow or outflow of a liquid material.
In particular, containers for storing highly volatile materials are made of iron having high durability.
In addition, a container cap to close a neck formed at an iron container includes: an inner cap closely coupled to an inner surface and an upper end of the neck and formed of a chemically resistant and soft synthetic resin material to secure sealing of the neck; and an outer cap formed of a rigid material to maintain a coupled state of the inner cap to the neck of a container.
The above-described inner cap is configured to be forcibly inserted into the inner surface of the container neck so that an outer diameter thereof is decreased, thereby being closely coupled thereto by elastic restoration force.
In addition, the inner cap is provided, at an upper end portion thereof, with a flange portion protruding outward so as to correspond to an upper end surface of the neck, and the flange portion is pressed by coupling of the outer cap to the neck to maintain the coupled state of the inner cap to the neck and also to complement the maintenance of sealing together with a lateral portion of the inner cap.
Meanwhile, the outer cap is configured to cover an upper portion of the neck and surround an outer side surface thereof around the upper portion, and is provided, at an inner circumferential surface thereof, with female threads to correspond to male threads of the container neck.
Opening the container cap having the above-described structure from the container neck is performed by the following two-step process. First, the outer cap is separated from the container neck by loosening threads. Subsequently, the portion of the inner cap, inserted into the neck, is separated therefrom by pulling the flange portion of the inner cap.
As such, the two-step container cap separation process is inconvenient, and has difficulty in separating the inner cap from the container neck and handling the contents of a container, with which the inner cap has been smeared (cases in which a toxic material, paint, or the like is smeared on a hand of a user or damages other parts thereof, and the like).
A conventional container cap includes an inner cap and an outer cap that are separately installed, and thus there is a possibility of loss of the inner cap or the outer cap.
To address these problems, Korean Patent Application Registration No. 10-0567206 (hereinafter referred to as ‘prior art 1’) and Korean Patent Application Registration No. 10-0671720 (hereinafter referred to as ‘prior art 2’) are disclosed by the present applicant.
Prior arts 1 and 2 have problems in terms of a great number of elements constituting a container cap, and a large number of operations according to coupling due to complicated coupling structures, which is not economical.
In addition, according to prior arts 1 and 2, an outer cap and an inner cap are connected to each other with an interval therebetween, and thus separation of the inner cap is performed after separation of the outer cap (step-wise processes). Moreover, the inner cap is elastically separated continuously after separation of the outer cap and, as a result, a material smeared on the inner cap may be spattered over the surroundings.
In addition, when storing the outer cap and the inner cap, a material smeared on a surface of the inner cap, contacting the material included in a container is smeared on the surroundings.